Conventionally, various techniques for a plurality of stator core segments have been proposed. For example, Japanese Patent Laying-Open No. 2009-118634 (PTL 1) proposes a rotating electric machine including core segments and a ring mounted on the outer circumference of the core segments, and including at least two or more projecting portions at a coupling section between adjacent core segments and at least one or more air gaps.
Japanese Patent Laying-Open No. 2009-153268 (PTL 2) proposes a structure, in a brush-less motor including a plurality of teeth and including a stator core, on the outer circumference of which a lightening hole extending in the axial direction is provided as a recess, wherein core segments are assembled to constitute the stator core and the stator core is press fit fixed within a casing, and a notch groove is formed in the axial direction in the inner circumferential surface in the casing.
Moreover, Japanese Patent Laying-Open No. 2007-259581 (PTL 3) proposes a stator wherein a yoke unit of each core segment is provided with a recess on its outer circumferential surface on the outer side of the motor radial direction, and a plurality of protrusions to be fitted within the recesses are provided in the inner circumferential surface of a holding ring.